SIR redraws Bengal’s margins of power

Voter deletions appear to have influenced close contests in constituencies with substantial minority populations.

The dramatic electoral debacle of the Trinamool Congress (TMC) in the West Bengal Assembly elections may be attributed to a wide range of factors, including strong anti-incumbency, allegations of large-scale corruption, and the fragmentation of minority votes. Yet, the Bharatiya Janata Party (BJP)’s success appears to have been shaped also by the Special Intensive Revision (SIR) of electoral rolls. The Election Commission of India (ECI)’s exercise saw one of India’s most extensive voter exclusions, which arguably played a decisive role in determining Mamata Banerjee’s electoral fate.

The BJP secured 292,24,804 votes against the TMC’s 260,13,377: a margin of 32,11,427 votes that translated into a 127-seat lead. This is significantly lower than the 91 lakh voters deleted during the revision, and even lower than the 66 lakh voters removed for reasons other than death.

Findings from an analysis of data from 293 Assembly seats are striking: in 161 of the 293 seats (54.8%), the number of voters deleted during the three SIR phases (Absent, Shifted or Dead/Duplicate [ASDD]; the final list of deletions on February 28; and the supplementary list deletions) exceeded the respective victory margin. This figure includes all categories of deletions, including deaths. Even after excluding deaths, the pattern remains significant. In 124 seats (42.2%), non-death deletions exceeded the winning margin.

Major concerns arise from the supplementary list deletions, which involved voters placed “under adjudication” and later reviewed by judicial officers. In 50 seats (17%), these deletions alone were greater than the margin of victory. The BJP won 207 seats in the election, while the TMC secured 80. Given the BJP’s much larger overall tally, it appears more frequently in the list of constituencies where voter deletions exceeded the victory margin.

The ECI undertook the SIR exercise in November 2025. In the first phase, Booth Level Officers (BLOs) carried out door-to-door voter verification. The initial list identified and excluded absent, shifted, dead, or duplicate voters from the draft rolls. The total number of such deletions stood at around 58 lakh. Another category included “unmapped voters” – individuals whose names could not be linked to the 2002 electoral rolls and were, therefore, marked for possible removal.

The preliminary data revealed an important pattern. Districts with higher Muslim populations, such as Murshidabad and Malda, showed relatively better levels of mapping. In contrast, a high incidence of unmapped voters was found among Matua communities in North 24 Parganas and Nadia.

In the second stage, the ECI introduced the category of “logical discrepancy”, using untested AI tools, under which voters were flagged for issues such as minor spelling variations or inconsistencies in the age gaps between parents and children. Some cases were placed “under adjudication” for hearings before Supreme Court-appointed judicial officers. After review, supplementary lists restored a small number of voters.

Among the 161 seats where total deletions exceeded the margin of victory, the BJP won 105, and the TMC won 53. Of the 124 seats where non-death deletions exceeded the margin, the BJP won 83 seats and the TMC, 38. In the 50 constituencies where supplementary list deletions alone were greater than the victory margins, the BJP and the TMC won 26 and 21 seats, respectively.

Of the BJP’s 207 seats, 105 had total deletions exceeding the victory margin. For the TMC, this figure was 53. TMC’s support is concentrated in Uttar Dinajpur, Malda, and Murshidabad – districts with large Muslim populations and high numbers of SIR-related deletions. The pattern persists after excluding deaths. Around 40.1% of the BJP’s seats (83 of 207) fell into the non-death deletion category, compared to 47.5% of the TMC’s seats (38 of 80).

The gap widens in the supplementary-list category. Only 26 of the BJP’s 207 victories (12.6%) were impacted by deletions exceeding the margin. For the TMC, the figure was 21 out of 80 seats (26.2%). In other words, more than one in four TMC victories fell into this category, compared to roughly one in eight BJP victories.

Varied patterns

The answer lies partly in demographic composition. The 207 seats the BJP won had an average minority population share of 15.1%, with a median of 12%. In contrast, TMC’s 80 seats had an average minority share of 41.2%, with a median of 36.9%. The nearly 26-point gap reflects the sharp demographic polarisation of the election.

Within the BJP’s seats, the minority share rose significantly in constituencies where deletions exceeded the margin. In the 83 BJP seats where non-death deletions were greater than the victory margin, the average minority population increased to 18.9%. In the 26 BJP seats where supplementary list deletions alone exceeded the margin, the average minority share rose further to 28%.

This suggests that the BJP’s victories were concentrated in constituencies with relatively higher minority populations: constituencies not traditionally considered the party’s strongholds. Of the 19 seats where the minority population was over 30%, the BJP won 18, even though the total non-BJP votes were higher than the BJP votes.

For the TMC, the pattern is somewhat different. In the 38 seats where non-death deletions exceeded the victory margin, the average minority share was 36%. In the 21 seats flagged under the supplementary-list category, the average minority share stood at 38.9%. Both figures are lower than the TMC’s overall average of 41.2%. This indicates that TMC’s strongest minority-dominated constituencies continued to produce sufficiently large victory margins to absorb the impact of deletions.

The real vulnerability appeared in constituencies with moderate minority populations, especially where minorities formed 20-40% of the population. In these seats, electoral contests were more competitive, and voter deletions could have significantly affected outcomes. For example, in Nandigram, Muslims constitute about 25% of the population, but deleted voters accounted for 94.5%. Similarly, in Bhabanipur, Muslims make up around 20% of the population; the deletions stood at 40.1%.

Both parties’ victories were concentrated in a similar electoral zone – constituencies with moderate minority populations, where relatively small changes in electoral rolls could have significant political consequences.

(The writers are associated with Sabar Institute, a research and
advocacy group)

Disclaimer: The views expressed above are the author's own. They do not necessarily reflect the views of DH.